<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <div id="app">
    <header>头部</header>
    <main>
      <div>1</div>
      <div>2</div>
      <div class="active">3</div>
      <div>4</div>
    </main>
    <footer>
      <b>首页</b>
      <b>分类</b>
      <b class="active">直播</b>
      <b>我的</b>
    </footer>
  </div>
</body>

</html>